Comet Streaks Through Cyberspace / Experts field Hyakutake questions over Internet in rare public science display

Charles Petit, Chronicle Science Writer

Published 4:00 am, Tuesday, March 26, 1996

The view of Comet Hyakutake was clear as a bell on the Internet yesterday, and questions for NASA scientists flew fast and furious from computer users all over the country taking part in the first- ever "virtual star party."

As professionals and amateur astronomers posted their pictures and asked questions, a panel of experts hunched over their terminals at the Mountain View facility.

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It was science on the fly, and perhaps more public than any natural spectacle in history as, thanks to instantaneous mass communication and access, researchers found themselves grappling with their data and a curious populace all the same time.

Diana of Miami wanted to know how long it would take a comet to melt, Jim of Virginia needed to know how fast the cosmic wayfarer was now traveling, and Carly of Boston asked how big it was and what kinds of gases were coming off it.

As for the answers: nobody knows how long it takes to melt a whole comet, Hyakutake is now traveling about 200,000 miles per hour or 100 times the speed of a bullet, and the solid nucleus is probably around ten miles across. The gases include cyanide, water and fragments of water molecules called hydroxyl ions, nitrogen-rich ammonium, formaldehyde, methyl alcohol, and a lot of odd organic molecules that resemble smog on Earth.

Other questions prompted longish essays. NASA scientist Lou Allamandola, for instance, speculated to the throngs of comet watchers that organic materials from comets were, billions of years ago, the fertilizer for the rise of life on Earth.

The comet passed within 9.3 million miles of Earth early Monday on the way to a close approach to the Sun May 1. From the Northern Hemisphere it should be visible in the evening sky through April.

While yesterday was the peak for the Internet project, it will continue through April with plenty of new pictures to look at and experts logging on regularly to answer questions. ^M

A lot of the questions concerned reports that the comet broke up yesterday into many pieces. "That one is hard to believe," said Scott Sandford, a scientist heading a different project to gather dust from a comet called Wild-2 and return it to Earth for analysis in the first decade of the next century.

A check of the Worldwide Web found, however, a report from the Pic du Midi Observatory in France, along with a picture, showing small fragments apparently drifting free of the main cometary nucleus. It hardly demonstrated major disintegration of the dirty snowball-like cometary body, but "that does look like some breakup," said Dale Cruikshank, a comet and solar system expert at Ames, as he looked over the images taken in France earlier yesterday and available on millions of computer screens around the world. In addition to facing a frenzy of public interest, scientists are starting to get some serious work done and plan to learn a great deal about Hyakutake, and comets in general, in coming months as they digest data from the closest comet passage in 20 years.

"The chemistry is where the action is," said Ames astronomer David Morrison. "That is where the clues are to how comets influenced the development of the environments of all the planets."

In just the past 10 years, planetary experts have come to believe that Earth, Mars, and Venus all were too hot and dry soon after formation to have had atmospheres at all like what they have today. Most of their gases, such scientists believe, were delivered by comets raining in from farther out in the solar system billions of years ago. While the number of comets is far lower now than then, and chances of collision also vastly smaller, such scientists know that, some day, a comet like Hyakutake will hit Earth again. The consequences could be catastrophic, for such a collision wiped out the dinosaurs, most experts say.

Though the science is fascinating, most members of the public simply find comets beautiful. With Hyakutake likely to remain easily visible for three or four more weeks, the questions and comments from the public are certain to continue.

Adam of Wisconsin had no question. He just chimed in, "It is the most spectacular thing I have ever seen."

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